The present invention relates to the construction of endless belts used to support a continuous web of liquid-penneable media and to transport the media through filtration apparatus for removing solid contaminants from liquids, typically those used as coolants and lubricants in machining operations, and the like.
Among the filtration systems commonly used to remove solid contaminants from liquids for recycling in machine tool operations are those wherein an endless chain or belt is moved through a tank to which contaminated liquid is supplied. A layer of liquid-previous media is carried on the upper surface of the chain, fresh media being supplied from a roll supported at the rear end of the tank and used media discharged at the front end. The media travels downwardly to some extent from the rear end as it enters the tank and thence upwardly to the front end. Dirty liquid is contained in a pool on the upper surface of the media between the tank side walls or other side structure and sealing means are provided to prevent escape of dirty liquid at the lateral edges of the media. Contaminants are deposited on the surface of the media as it travels through the tank, the clean liquid which passes through the media being collected in the lower part of the tank and pumped back to the location of the machining operation.
The endless belts used in such filtration apparatus are subjected to rather high tensile forces, particularly when a subatmospheric pressure is created in the space below the pool of contaminated liquid on the upper side of the media in order to increase the filtration rate. Consequently, the belt must have a tensile strength adequate to withstand such forces. In general, the higher the strength of the belt, the higher its cost in terms of materials, assembly costs, or both.
It is a principal object of the present invention to provide a continuous belt for use in supporting and transporting filter media in liquid filtration apparatus wherein the strength to cost ratio of the belt is significantly improved. That is, the invention seeks to reduce the cost of endless belts used in liquid filtration apparatus without reducing the tensile strength of the belt or compromising any of its other operational characteristics.
Other objects will in part be obvious and will in part appear hereinafter.